Locking mechanism



June 22, 1943.

LOCKING AMEGI'IANISM Filed Aug. 5, 1942 INVENT-OR." @yA/fm1' JMA/f7 c. J. s'ruAR-r 2,322,402

Patented June `22, 1943 LOCKING DIECHANISM Charles J. Stuart, Winchester, Mass., assignor to Wellman Company, Medford, Mass., a corporation of Maine Application August 5, 1942, Serial No. 453,689

3 Claims.

This invention relates to an improved mechanism for locking a rotatable member on a shafty and particularly to the means for preventing the rotation of one of the locking members.

The invention is an improvement upon the locking adjustment disclosed in my co-pending application Serial No. 364,964, led November 9,

1940, comprising an adjusting hand wheel rotat-4 ably mounted on a shaft, a manually operable locking member, and a locking disc non-rotatably mounted on a shaft between the hand wheel and the manually operable locking member. The non-rotatable locking disc is adapted to be clamped by the locking nut between and in frictional engagement with the locking nut and the hand wheel to prevent the latter from rotating after an adjustment has been made by turning the hand wheel. The purpose is to provide a secure and releasable locking mechanism. This improvement consists primarily in the simplified construction of the locking disc and the means for non-rotatably mounting the disc on the shaft.

The invention will be described in detail in connection with the accompanying drawing, in which:

' Fig. 1 is a longitudinal cross-sectional view of the locking mechanism embodying the invention;

Fig. 2 is a sectional view on line 2-2 of Fig. 1; and

Fig. 3 is a fragmentary cross-sectional view of a modified form of the invention.

The invention is illustrated herein in connection with a mechanism for changing the eccentricity of a crank pin on a crank disc. The crank disc IIJ is rotated by a shaft The disc I is provided with a dovetail groove |`2', in which is slidably mounted a head I3 of the crank pin, or shaft |4. A rack I5 is secured to the crank disc ID by means of screws I6. The pin I4 may be moved along the groove I2 to adjust its eccentricity in respect to the shaft II by means of a pinion |I rotatably mounted on the crank pin I4, and meshing with the teeth of the rack I5. The pinion |'I is operated by a hand wheel I8 keyed to the sleeve I9 of the pinion I'I by a key 20. Rotatably mounted on the sleeve I9 betweenthe pinion |'I and the hand wheel I8 is a crank pin block I9 forming the connection with a member to be operated by the crank pin I4, which construction is more particularly shown in United States Patent No. 1,270,319 in Fig. 5 by member 55.

The hand wheel I8 is locked in any desired position by a manually operable member, or locking nut 2 I, having a threaded internal bore 22 cooperating with the threaded portion 23l of the crank pin |4.

As shown in Fig. 1 a nut 24 is screwed onto the threaded portion 23 and is keyed thereto by a pin 25 passing diametrically through the nut and the crank pin I4. As shown in Fig. 2, the nut 24 has non-circular outer walls, and as specifically shown the walls are square. A spring cup-shaped locking disc 26 is provided with a central opening 21 conforming to the shape of the outer walls of the nut 24, and it is slidably and non-rotatably mounted on the outer walls of the nut 24, the non-circular walls being adapted to prevent rotation. The outer perimeter 28 of the locking disc 26 is provided with frictional surfaces which contact with the frictional surface 29 located in a recess 36 on the hand wheel I8. The locking nut 2| is provided with a frictional surface 3| having a radius substantially equal to the radius of the frictional surface on the outer perimeter of the locking disc 26 and located a substantial distance from its axis of rotation so as to provide a relatively long lever arm for the frictional forces to act upon. When the locking nut is turned so as to move its frictional surface 3| in contact with the locking disc 26, the frictional surface 2'8 on the disc is moved in contact with the frictional surface 29 on the hand wheel I8.

When the locking nut 2| is turned down tight, the hand wheel I8 is frictionally locked against rotation on the crank pin I 4 by the friction between the surface 29 on the hand wheel I 8 and the nonrotatable frictional surface 28 on the locking disc 26. Since the radii of the frictional surfaces 28, 29, and 3| are relatively long the wheel I8 is securely locked in place as well as the locking nut 2|, and it requires a relatively large torque force to rotate the hand wheel I8 and loosen the locking nut 2| when it is in its locking position.

In the modification of the invention shown in Fig. 3 the locking disc 26 is locked against rotation on the shaft I4 by means of a bushing 32 having non-circular outer walls 33. The bushing' 32 is keyed to the non-threaded portion of the shaft I4 by means of a pin 34. The locking disc 26 is provided with a central opening 35 which conforms to the shape of the outer walls 33 of the bushing 32 and is slidably and non-rotatably mounted thereon. The locking disc cooperates with the hand wheel I8 and is operated by the locking nut 2| in the same manner as shown in Fig. 1.

The construction of the locking discs 26 and the nut 24, or bushing 32 is advantageous because the disc can be easily stamped out and a standard nut'or bushing may be used. A saving of metal and some machining of the metal parts is effected.

The preferred forms of this invention have been described and it will be understood that changes in the details may be made without departure from the spirit of the invention and the scope of the appended claims.

Having thus described my invention, whatI I claim and4 desire to protect by Letters Patent is:

1. A mechanism for locking an adjusting member against rotation on a shaft comprising threads on one end of s'aid shaft and an enlarged anchoring base on the other end, a locking nut cooperating with said threads, a member having noncircular outer walls adapted to pass over said threads, means for fixing said non-circular member against movement on said shaft between said adjusting member and said nut, a locking disc having a central opening adapted to slidably t and to be held against rotation by the non-circular walls of said member xed' on said shaft, said disc having its peripheral surface. adapted to contact with said adjusting member, and said locking nut being adapted to be screwed' against said disc to move its peripheral surface into frictional engagement with said adjusting member.

2. A mechanism for locking an adjusting hand wheel against rotation on a shaft comprising threads on theY end of said shaft and an enlarged anchoring base on the other end, a locking nut cooperating with said threads, a member having non-circular outer walls adapted to pass over said threads, means for fixing said non-circular member against movement on said shaft between said hand wheel and said nut, a spring locking disc having a central opening adapted to slidably fit and to be held against rotation by the noncircular walls of said member Xedon said shaft, said disc having its peripheral surface adapted to Contact with said wheel, and said locking nut being adapted to be screwed against said disc near its outer periphery to move its peripheral surface into frictional engagement with said wheel.

3.v A mechanism for locking an adjusting hand wheel against rotation on a shaft comprising threads on the end of said shaft, a locking nut cooperating with said threads, a second nut having non-circular outer walls screwed on said threads and keyed to said shaft between said hand wheel and said locking nut, a spring locking disc having aV central opening adapted to slidably t and to be held against rotation bythe non-circular walls of said second-nut, said disc having its peripheral surface adapted to Contact with said wheel, and said locking nut being adapted to be screwed against said disc to move its peripheral surface into frictional. engagement with said wheel.

CHARLES J. STUART. 

